Scenario A – In a famous study that began in 1948, a sample population in Framingham, Massachusetts, was selected and followed through the course of their lives. They were periodically tested to see if they had developed one of several types of heart disease. Scenario B – In a study of pregnant women, researchers reviewed medical histories and found that women who were diagnosed with gestational breast cancer were more likely to have their labor induced preterm than pregnant women who were not diagnosed. Complete the sentences by selecting the correct study type.